Can anybody tell me why I should buy them?
French infantry of the line with cross belts. This mistake has been done already last century.
It's a pity, nice figures, but.....

I will be buying them very similar poses to the old guard at ease but I guess that was going to be obvious. liking the different headgear ads a bit of interest.

Yes, WHY crossbelts but no epaulettes? Has there been a re-think about what I thought was the well-known position that fusiliers had one belt, over the left shoulder and carrying the bayonet frog as well as the cartridge pouch, and only elites (voltigeurs and grenadiers) had crossbelts, plumes, epaulettes? This would make me hesitate to buy what are otherwise very nice figures, I'm afraid.

Crossbelts are not for line infantry, however you could consider using these figures as light infantry in great coats, they seem to have the infantry saber. Epaulettes were at a certain time exclusively reserved for the elites. That light infantry continued to wear them, was much to the little big man's dismay. Perhaps these units kept the swords and especially on the greatcoats, compromised on the epaulettes. Headgear is not a problem either, en route plumes were usually removed. Paint the pompoms either red or yellow or dark green and you might get a decent representation of light infantry. Alternatively, there is milliput to play with.